Susan Michaelis, Ph.D.
Professor of Cell Biology
Room 104, Biophysics Building
Progeria and lamin A processing; protein quality control mediated by the ubiquitin-proteasome system; mammalian and yeast cell biology.
We study fundamental cellular processes relevant to human disease. A major research focus in our laboratory is the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS), which results from a mutation in the gene encoding the nuclear scaffold protein lamin A. Children with HGPS exhibit profound characteristics of aging, including hair loss, skin and bone defects, and heart disease. The mutant form of lamin A in HGPS patient cells is persistently modified by the lipid farnesyl, an aberrant situation, since normally cleavage by the ZMPSTE24 protease removes the farnesylated C-terminal tail of lamin A during biogenesis. We are examining the cell biology of lamin A processing, the molecular mechanisms of lamin A toxicity in HGPS, mechanistic features of the ZMPSTE24 membrane protease, therapeutic strategies, and the link between HGPS and normal aging.
We also study protein quality control mediated by the ubiquitin-proteasome system. Misfolded secretory and membrane proteins are efficiently degraded by ER-associated degradation (ERAD), while cytosolic quality control (CytoQC) pathways handle misfolded soluble proteins. Our goal is to identify the core cellular machinery involved in recognition of misfolded proteins, using model proteins as 'bait' in genome-wide yeast screens designed to uncover the eukaryotic ERAD and CytoQC machinery. Ultimately, devising treatment for protein misfolding diseases such as cystic fibrosis or Parkinson’s will require a detailed understanding of the cellular protein quality control machinery.
10. Barrowman, J., Hamblet, C., George, C.M., and Michaelis, S. (2008) Analysis of prelamin A biogenesis reveals the nucleus to be a CaaX processing compartment. Mol. Biol. Cell 12:5398-5408 PMC2592638
11. Hudon, S. E., Coffinier, C., Michaelis, S., Fong, L. G., Young, S. G., and Hrycyna, C. A. (2008) HIV-Protease inhibitors block the enzymatic activity of purified Ste24p. Biochem Biophys Res Comm. 374:365-368 PMC2543933
12. Nakatsukasa, K., Huyer, G., Michaelis, S., and Brodsky J. L. (2008) Dissecting the ER-Associated Degradation of a Misfolded Polytopic Membrane Protein. Cell 132: 101-112. PMC2219389
13. Paumi, C. M., Menendez, J., Arnoldo, A, Engels, K, Iyer, K. R., Thaminy, S, Georgiev, O., Barral Y., *Michaelis, S, and *Stagljar, I. (2007) Mapping Protein-Protein Interactions for the Yeast ABC Transporter Ycf1p by Integrated Split-Ubiquitin Membrane Yeast Two-Hybrid (iMYTH) Analysis. Molecular Cell 26: 15-25. * Co-corresponding senior authors. PMID: 17434123
14. Mallampalli, M. P., Huyer, G., Bendale, P., Gelb, M. H., and Michaelis, S. (2005) Inhibiting Farnesylation Reverses the Nuclear Morphology Defect in a HeLa Cell Model for Hutchinson-Gilford Progeria Syndrome, Proc Natl. Acad Sci. USA 102:14416-14421. PMC1242289
15. Young, S. G. Fong, L., and Michaelis, S. (2005) Prelamin A, Zmpste24, misshapen cell nuclei, and progeria- new evidence suggesting that protein farnesylation could be important for disease pathogenesis. Journal of Lipid Research 46:2531-2558. PMID: 16207929